100+ Interview Questions and Answers

Explanation of differences between programming concepts and techniques.

• Procedure vs Function: Functions return a value while procedures do not.

• Delete vs Truncate: Delete removes rows one by one while truncate removes all rows at once.

• Exit vs In: Exit is used to exit a loop or a program while In is used to pass values into a subprogram.

• Cursor vs Bulk Bind: Cursor fetches one row at a time while Bulk Bind fetches multiple rows at once.

• Cursor vs Collection: Cursor is used to fet...read more

OOP stands for Object-Oriented Programming. It is a programming paradigm based on the concept of objects, which can contain data and code.

• Main method can be overloaded in Java by defining multiple methods with the same name but different parameters.

• Abstraction in OOP is the concept of hiding the implementation details and showing only the necessary features of an object. Example: Car as an object with properties like color, model, and methods like start, stop.

• Inheritance in J...read more

Array is a fixed-size collection of elements, while stack is a data structure that follows Last In First Out (LIFO) principle.

• Array is a static data structure, while stack is a dynamic data structure.

• In array, elements are accessed using index, while in stack, elements are accessed using push and pop operations.

• Linked list is a data structure where each element points to the next element, types include singly linked list, doubly linked list, and circular linked list.

• Advantage...read more

Questions related to Java programming language and Spring framework

• Inheritance is a mechanism in Java where a class acquires the properties of another class

• Spring Boot is a popular framework for building web applications in Java

• Advantages of Spring Boot include easy configuration, auto-configuration, and embedded servers

• Spring annotations are used to provide metadata to the Spring framework

• Some common Spring annotations include @Autowired, @Controller, and @Service

• Design patt...read more

Improving performance, connecting to multiple databases, and developing REST API in a Spring application.

• To improve performance, use caching mechanisms like Spring Cache or Redis.

• To connect to 2 databases, configure multiple DataSource beans in the application context.

• To develop a REST API in Spring Boot, use @RestController annotation and define request mappings.

UiPath has introduced new features like AI Fabric, Document Understanding, and improved automation capabilities.

• Introduction of AI Fabric for integrating AI models into automation workflows

• Enhanced Document Understanding capabilities for processing unstructured data

• Improved automation capabilities with features like Task Capture and Task Mining

Use a self join to remove duplicate rows in a table without using distinct.

• Join the table with itself on the columns that define duplicates

• Filter out rows where the primary key is the same but other columns are different

• Select only distinct rows based on the primary key

Yes, it is possible to create multiple foreign keys in a single table.

• Multiple foreign keys can be created in a single table by referencing different columns in the same or different tables.

• Each foreign key constraint must be defined separately with appropriate references.

• Foreign keys help maintain referential integrity between tables in a database.

• Example: Creating foreign keys in a 'Orders' table to reference 'Customers' and 'Products' tables.

I would communicate with the stakeholders to understand the reasons for the changes and prioritize them accordingly.

• Communicate with stakeholders to understand the reasons for the changes

• Prioritize the changes based on impact and urgency

• Adjust the sprint plan and tasks accordingly

• Ensure clear documentation and communication with the team

OOP stands for Object-Oriented Programming. It is a programming paradigm that uses objects to represent and manipulate data.

• OOP focuses on creating reusable code through the use of classes and objects.

• It emphasizes encapsulation, inheritance, and polymorphism.

• Encapsulation refers to the practice of hiding the internal workings of an object from the outside world.

• Inheritance allows classes to inherit properties and methods from other classes.

• Polymorphism allows objects to take...read more

Collection is a framework in Java that provides an architecture to store and manipulate a group of objects.

• Arrays are a fixed-size collection of elements of the same data type.

• Collections are dynamic and can grow or shrink in size.

• Arrays use square brackets to declare and initialize, while collections use classes like ArrayList or LinkedList.

• Collections provide many useful methods like add(), remove(), and size().

It depends on the specific requirements and constraints of the application.

• Use entity base delete for simple operations where ORM can handle cascading deletes and relationships.

• Use native query for complex operations or when performance is a concern.

• Consider the impact on database integrity and consistency when choosing between entity base and native query.

Roll-up and scan components are both used in data processing, but they have different functions and purposes.

• Roll-up is a data aggregation technique that summarizes data at a higher level of granularity.

• Scan component, on the other hand, is used to read and process data sequentially.

• Roll-up is commonly used in data warehousing to generate summary reports or perform calculations on aggregated data.

• Scan component is often used in data processing pipelines to iterate through lar...read more

String is immutable while StringBuffer is mutable.

• StringBuffer can be modified while String cannot.

• StringBuffer is thread-safe while String is not.

• StringBuffer has append() method while String does not.

• StringBuffer is slower than String for simple operations.

final is a keyword used to declare a constant variable, finally is a block used in try-catch-finally, and finalize is a method used for garbage collection.

• final is used to declare a constant variable that cannot be changed

• finally is a block used in try-catch-finally to execute code regardless of whether an exception is thrown or not

• finalize is a method used for garbage collection to perform any necessary cleanup actions before an object is destroyed

• All three keywords are unre...read more

Use bitwise AND operation to determine if a number is odd or even.

• Use bitwise AND operation with 1 to check if the least significant bit is 1 or 0.

• If the result is 1, the number is odd. If the result is 0, the number is even.

• Example: num & 1 will return 1 for odd numbers and 0 for even numbers.

There are 4 transitions in RE Framework: Init, Get Transaction Data, Process Transaction, and End Process.

• Init - Initializes the application, opens applications, logs in, and sets up environment.

• Get Transaction Data - Retrieves transaction data from queue or data source.

• Process Transaction - Processes the transaction data, performs necessary actions, and updates status.

• End Process - Cleans up resources, logs out, and closes applications.

Hooks are functions that allow you to tap into the lifecycle of a component in Angular.

• Hooks are used to perform actions at specific points in the component's lifecycle.

• There are several types of hooks, including ngOnInit, ngOnChanges, and ngOnDestroy.

• ngOnInit is called once when the component is initialized.

• ngOnChanges is called when the component's input properties change.

• ngOnDestroy is called just before the component is destroyed.

Abstract functions cannot be instantiated and must be implemented by child classes, while normal functions can be directly called.

• Abstract functions have no implementation in the parent class, while normal functions do.

• Abstract functions are declared with the 'abstract' keyword, while normal functions are not.

• Normal functions can be called directly, while abstract functions must be implemented by child classes.

• An example of an abstract function is 'draw' in a 'Shape' class, w...read more

ConcurrentHashMap is thread-safe and allows concurrent access, while HashMap is not thread-safe and can lead to race conditions.

• Use ConcurrentHashMap when multiple threads need to access and modify the map concurrently.

• Use HashMap when only a single thread will be accessing or modifying the map.

• ConcurrentHashMap is more suitable for high-concurrency scenarios like multi-threaded applications.

• HashMap is faster for single-threaded operations due to lack of synchronization overh...read more

Creating forms in Drupal with code explanation

• Use the Drupal Form API to create forms

• Define form elements using the Form API functions

• Implement form validation and submission handlers

• Use hook_form_alter to modify existing forms

I will listen to their concerns, empathize with their situation, and work towards finding a solution that meets their needs.

• Listen actively to understand their concerns

• Empathize with their situation to show understanding and build rapport

• Work collaboratively to find a solution that meets their needs

• Maintain professionalism and patience throughout the interaction

Security for RESTful webservices is provided through authentication, authorization, encryption, and input validation.

• Implement authentication mechanisms such as OAuth, JWT, or API keys to verify the identity of clients accessing the services.

• Use authorization techniques like role-based access control (RBAC) or attribute-based access control (ABAC) to control what actions users can perform.

• Encrypt sensitive data using SSL/TLS to ensure secure communication between clients and ...read more

Use Java 8 stream to find the 2nd largest number in an array of strings.

• Convert the array of strings to an array of integers using stream and map function.

• Sort the array in descending order using sorted() method.

• Skip the first element to get the second largest number using skip() method.

Abstract classes can have implementation while interfaces cannot.

• Abstract classes can have constructors while interfaces cannot.

• A class can implement multiple interfaces but can only inherit from one abstract class.

• Abstract classes can have non-abstract methods while interfaces can only have abstract methods.

• Interfaces are used for full abstraction while abstract classes are used for partial abstraction.

• Example of abstract class: public abstract class Animal { public void eat...read more

Data structures in C++ are used to organize and store data efficiently.

• C++ provides various built-in data structures like arrays, linked lists, stacks, queues, trees, and graphs.

• These data structures can be used to store and manipulate data in an efficient manner.

• C++ also allows for the creation of user-defined data structures using classes and structures.

• The choice of data structure depends on the type of data and the operations that need to be performed on it.

C is a procedural programming language while C++ is an object-oriented programming language.

• C is a procedural programming language, while C++ is a multi-paradigm language that supports procedural, object-oriented, and generic programming.

• C does not support classes and objects, while C++ does.

• C does not have built-in support for exception handling, while C++ does with try-catch blocks.

• C does not have namespaces, while C++ does to avoid naming conflicts.

• C does not have function...read more

SDLC stands for Software Development Life Cycle, a process used by software engineers to design, develop, and test software applications.

• SDLC is a structured process that consists of several phases including planning, analysis, design, implementation, testing, and maintenance.

• Each phase of SDLC has its own set of activities and deliverables to ensure the successful completion of the software project.

• Examples of SDLC models include Waterfall, Agile, and DevOps, each with its o...read more

To make a class immutable, its state should not be modifiable after creation.

• Make all fields private and final

• Do not provide any setters

• If mutable objects are used, return copies instead of references

• Ensure that the class cannot be extended

• Consider making the constructor private and providing a factory method

An abstract function is a function that has no implementation and must be implemented by its subclasses.

• An abstract function is declared with the 'abstract' keyword.

• It is used to define a template for its subclasses to follow.

• It cannot be instantiated and must be implemented by its subclasses.

• It can have abstract and non-abstract methods.

• Example: abstract class Animal { abstract void makeSound(); }

• Example: class Dog extends Animal { void makeSound() { System.out.println('Bark...read more

Object-oriented programming concepts in Java include inheritance, encapsulation, polymorphism, and abstraction.

• Inheritance allows a class to inherit properties and behavior from another class.

• Encapsulation involves bundling data and methods that operate on the data into a single unit.

• Polymorphism allows objects to be treated as instances of their parent class.

• Abstraction hides the implementation details and only shows the necessary features of an object.